#include <stdio.h>



int erfenfind(int *arr,int findnum,int len)
{
	int a=0;
	int b=len-1;
	int mid=(a+b)/2;
	while(1)
	{
		if(findnum == arr[mid])
		{
			return mid;
		}
		if(findnum == arr[a])
		{
			return a;
		}
		if(findnum == arr[b])
		{
			return b;
		}
		if(findnum > arr[mid])
		{
			a = mid;
			mid = (a+b)/2;
		}
		else
		{
			b = mid;
			mid = (a+b)/2;
		}
		if(a+1==b&&findnum!=arr[a]&&findnum!=arr[b])
		{
			return -1;
		}
	}
}

int main(int argc, const char *argv[])
{
	int findnum=0;
	int arr[10]={1,3,5,7,9,11,13,15,17,19};
	scanf("%d",&findnum);
	int len=sizeof(arr)/4;
	int ret=erfenfind(arr,findnum,len);
	if(ret>=0)
	{
		printf("yes pos = %d \n",ret);
	}
	else
	{
		printf("no\n");
	}

	return 0;
}
